Health GIS and COVID-19: A Case Study of West Bengal State, India
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4.4. RELATION BETWEEN NO2 AND COVID-19
It has been demonstrated that long-term exposure to air pollution is associated with
an increased prevalence of respiratory diseases and deaths. Fine particulate matter with size
<2.5 μm, PM2.5 is considered is one of the major health risk factors in the environment,
causing millions of deaths annually around the world. The presence of PM2.5 and another
one also PM10 are specifically associated with an increased rate of respiratory diseases,
and of hospitalization for chronic lung disease and pneumonia. Nitrogen dioxide (NO2) is
another important air pollutant that is toxic to human respiratory systems when present at
higher concentrations in the atmosphere It enters the atmosphere as a result of both
anthropogenic and natural processes. As the outdoor anthropogenic sources, NO2 is mainly
emitted from fuel combustion and transportation, in general, they come to the air from
vehicle exhaust gases and domestic heating. NO2 exerts adverse effects mainly on the
respiratory system, however, prolonged exposure to NO2 is correlated with a wide range
of severe illnesses such as hypertension, diabetes, and cardiovascular diseases and causes
even death. An early study also showed that chronic exposure to NO2 causes cytokine-
mediated inflammation in the lungs. Air pollution-related deaths include but are not
limited to bronchitis, aggravated asthma, respiratory allergies, heart disease, and stroke.
Exposure to air pollution especially NO2 and PM2.5 may increase the susceptibility
of infection and mortality from COVID-19. The available data also indicate that exposure
to air pollution may influence COVID-19 transmission. Moreover, air pollution can cause
adverse effects on the prognosis of patients affected by SARS-CoV-2 infection. The
available research findings on this topic may help the epidemiologists to select a proper
measure to prevent such an outbreak in the future. Attention should also be paid to the poor
communities, who are susceptible to be exposed to indoor air pollution, contributing to a
greater risk of becoming severely ill from COVID-19 infections. Air quality should be
counted as an important part of an integrated approach toward public health protection and
prevention to the spread of epidemics. Further research should be conducted focusing on
additional confounders such as age and pre-existing medical conditions along with